Find Duplicate or Repeating Words in String Using PHP 7

<?php  
$string = "Small brown bug bit a small brown dog on his small brown nose";  
$count;  
   
//Converts the string into lowercase  
$string = strtolower($string);  
   
//Split the string into words using built-in function  
$words = explode(" ", $string);  
   
print("Duplicate words in a given string : <br>");  
for($i = 0; $i < count($words); $i++) {  
    $count = 1;  
    for($j = $i+1; $j < count($words); $j++) {  
        if($words[$i] == $words[$j]) {  
            $count++;  
            //Set words[j] to 0 to avoid printing visited word  
            $words[$j] = "0";  
        }  
    }  
      
    //Displays the duplicate word if count is greater than 1  
    if($count > 1 && $words[$i] != "0"){  
        print($words[$i]);  
        print("<br>");  
    }  
}  
?>